a Only air-cooled single-packaged and split system units used in commercial buildings are covered. Water source units are not covered by ENERGY STAR? but look for efficiency ratings that meet or exceed these levels for air source units.
b When operating conditions are often close to rated conditions or in regions where there are high demand costs, look for units with the highest EER ratings that also meet or exceed this SEER.

EER (energy efficiency ratio) is the cooling capacity (in Btu/hour) of the unit divided by its electrical input (in watts) at the Air Conditioning and Refrigeration Institute's (ARI) standard peak rating condition of 95¡ãF.

SEER (seasonal energy efficiency ratio) and IPLV (integrated part-load value) are similar to EER but weigh performance at different (peak and off-peak) conditions during the cooling season.